• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A3cd+4cd

Red List history

Year	Category	Criteria
2020	Vulnerable	A3cd+4cd
2018	Vulnerable	A3cd+4cd
2016	Near Threatened	A2cd+3cd+4cd; C1
2013	Near Threatened	A2cd+3cd+4cd; C1
2012	Near Threatened	A2cd+3cd+4cd;C1
2008	Near Threatened	A2c,d; A3c,d; A4c,d; C1
2004	Near Threatened
2000	Lower Risk/Near Threatened
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	high
Land-mass type	continent shelf island	Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	10,300,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	13000-27000 mature individuals	poor	inferred	-
Population trend	decreasing	medium	suspected	1989-2043
Rate of change over the future 10 years/3 generations (longer of the two periods)	30-39%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	30-39%	-	-	-
Generation length	18.3 years	-	-	-

Population justification: The population density of the Great Hornbill has been estimated from across several sites in its range. In Arunachal Pradesh in north-east India, the density of Great Hornbill in Namdapha Tiger Reserve was estimated to be around 4 birds per km² (Naniwadekar and Datta, 2013) in the non-breeding season and this was similar in Pakke Tiger Reserve at 3.8 birds per km² (Datta et al. unpublished data 2014). In Pakke Tiger Reserve, its overall density was estimated to be around 12 birds per km² in an earlier study (Dasgupta and Hilaluddin, 2012). The density was estimated to be 1 bird per km² in forests outside Namdapha Tiger Reserve (Naniwadekar et al. 2015a). In the rainforest fragments, the densities  ranged from 3.4 to 10 birds per km² (Raman & Mudappa, 2003). The density of Great Hornbill ranged between 1.5-4.4 individuals/km² in Anamalai and Parambikulam Tiger Reserves, 0-4 individuals per km² in Reserved Forests of Vazhachal-Sholayar and Malayattur and 0.6-4.5 individuals per km² in rainforest fragments in Anamalai Hills (Mudappa & Raman, 2009). Densities are higher in Anamalai Tiger Reserve (~4 birds/ km²) as opposed to the adjoining shade coffee plantations (~2 birds/ km²) based on line-transect surveys between January 2017 and April 2018 (Pawar et al. unpublished data).
In Thailand, its population density has been estimated to range between 1.3-4.7 birds per km² in Huai Kha Khaeng Wildlife Sanctuary, Thung Yai Naresuan Wildlife Sanctuary, Khao Yai National Park, and Budo Sangai Padi National Park. It ranges between 0.04-1.1 birds per km² in nine other forest complexes in Thailand (Gale and Thongaree 2006, Jornburom et al. 2010, Poonswad et al. 2013). 

These population densities indicate that the population within these sites, given the approximate habitat that lies within a suitable elevation range, can be estimated on a precautionary basis at 23,000 - 71,000 individuals. This is placed in the band 20 - 49,999 individuals, roughly equating to 13,000 - 27,000 mature individuals. Outside protected areas, even if adjacent, population densities can be considerably lower, often well below 1 individual per km² (Gale and Thongaree 2006, Mudappa and Raman 2009, Naniwadekar et al. 2015), and it has been driven to local extinction across several sites both inside and outside Protected Areas in Arunachal Pradesh (Datta 2002, Naniwadekar et al. 2015a).

Trend justification: An analysis of deforestation between 2000 and 2012 estimated forest loss within the species's range at 26.1% over three generation lengths (55.2 years) (Tracewski et al. 2016). The species is generally intolerant of forest disturbance and additionally severely threatened by hunting. Thus, its actual rate of population decline is likely greater than the estimate decline based on forest loss alone. The rate of decline is tentatively placed in the band 30-49% over three generations. Since this species has a long generation length, with three generations stretching over 55 years, there is insufficient evidence to calculate the magnitude of reduction over the past three generations. Assuming the recent rate of decline remains constant, the species is projected to decline by 30-49% over the next three generations.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Bangladesh	extant	native	yes
Bhutan	extant	native	yes
Cambodia	extant	native	yes
China (mainland)	extant	native	yes
India	extant	native	yes
Indonesia	extant	native	yes
Laos	extant	native	yes
Malaysia	extant	native	yes
Myanmar	extant	native	yes
Nepal	extant	native	yes
Thailand	extant	native	yes
Vietnam	extant	native	yes

Country/Territory	IBA Name
Cambodia	Central Cardamoms
Cambodia	Phnom Aural
Cambodia	Phnom Bokor
Cambodia	Phnom Samkos
Nepal	Barandabhar forests and wetlands
Nepal	Bardia National Park
Nepal	Chitwan National Park
Nepal	Mai Valley forests
Nepal	Parsa Wildlife Reserve
Vietnam	Ea So
Vietnam	Kon Cha Rang
Vietnam	Yok Don

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	major	resident
Artificial/Terrestrial	Rural Gardens	major	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	0 - 2000 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Agro-industry plantations	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Species mortality
Biological resource use	Hunting & trapping terrestrial animals - Unintentional effects (species is not the target)	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Scale
Food - human	subsistence, national
Medicine - human & veterinary	subsistence, national
Pets/display animals, horticulture	international

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Recommended citation
BirdLife International (2024) Species factsheet: Great Hornbill Buceros bicornis. Downloaded from https://datazone.birdlife.org/species/factsheet/great-hornbill-buceros-bicornis on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/11/2024.